[Developing an avirulent mutant of Aujeszky's disease virus using the effect of 5 bromodesoxyuridine]

Chemicals are being used increasingly in the preparation of vaccines. Thus, an effective vaccine (MK25) against Aujeszky's Disease showing stable genetic characteristics was produced by having 5 iododesoxyuridine exert its action on a particular strain of virus. 5 Bromo-desoxyuridine also has an inhibitory effect on the synthesis of DNA viruses. The development of a new mutant of Aujeszky's Disease virus using this agent is reported. The resulting mutant, MK35, was found to be biologically stable, non-pathogenic for white mice, rabbits, sheep and piglets and, in addition, produced stable immunity in piglets, sheep and rabbits within four days after injection of this mutant.